[Stability characteristics of soil organic carbon pool following development of sand-fixing forest in Mu Us sandy land, China].

The study aimed to reveal the cumulative effects and stability characteristics of soil organic carbon (SOC) during forest development at the Mu Us sandy land, China. Using space for time substitution, surface soil samples were collected from semi-fixed sandy lands and restored arbor and shrub lands with the ages of 22, 32 and 53 years in the Yulin sand control region in Northern Shaanxi Province. The content of total organic carbon (TOC), oxidizable labile organic carbon, and resistant carbon and the characteristics of mineralized carbon emission and decomposition ratio were analyzed.

[Carbon sequestration in soil particle-sized fractions during reversion of desertification at Mu Us Sand land.].

The aim of this study was to investigate the effects of carbon sequestration in soil particle-sized fractions during reversion of desertification at Mu Us Sand Land, soil samples were collected from quicksand land, semifixed sand and fixed sand lands that were established by the shrub for 20-55 year-old and the arbor for 20-50 year-old at sand control region of Yulin in Northern Shaanxi Province. The dynamics and sequestration rate of soil organic carbon (SOC) associated with sand, silt and clay were measured by physical fractionation method. The results indicated that, compared with quicksand area, the carbon content in total SOC and all soil particle-sized fractions at bothsand-fixing sand forest lands showed a significant increasing trend, and the maximum carbon content was observed in the top layer of soils.

Alkaloids and sesquiterpenoids from Acorus tatarinowii.

The rhizome of Acorus tatarinowii is a well-known traditional Chinese medicine. Our extensive investigation on this plant material afforded two new compounds, including a cadinane-type sesquiterpenoid and a pyrazine derivative, along with seven known compounds. The structures of the new compounds, tatarinowin B and tatarinine A, were elucidated as 2-oxocadinan-1(10),3-dien-5-ol (1) and 2-(3',4'-dihydroxy-1'-butylenyl)-5-(2'',3'',4''-trihydroxybutyl)-pyrazine (2), respectively, by means of spectral methods.

A new pregnane steroid from Poria cum radix pini.

A new pregnane steroid and eight known compounds were isolated from Poria cum radix pini. Their structures were identified by spectroscopic data. All the known compounds were isolated from this species for the first time.

Compounds from Acorus tatarinowii: determination of absolute configuration by quantum computations and cAMP regulation activity.

A new cadinane-type sesquiterpenoid, tatarinowin A (1), two phenylpropanoids, tatarinoids A (2) and B (3), and a trinorlignan, tatarinoid C (4), along with 15 known compounds including two pairs of mixtures were isolated from the rhizome of Acorus tatarinowii. The absolute configurations of 1-4 were established by computation of specific rotation values. The isolated compounds were evaluated for their cAMP regulatory activity by the AlphaScreen assay.

[Content and evolution characteristics of organic carbon associated with particle-size fractions of grey desert soil under long-term fertilization].

Physical fractionation technique was used to analyze the content, distribution, and temporal evolution of organic carbon associated with particle-size fractions of grey desert soil under long-term (1990-2007) fertilization. Compared with no fertilization, a combined application of manure and chemical fertilizers increased the organic carbon associated with particle-size fractions significantly, with the highest increment (0.34 g x kg(-1) x a(-1)) in sand.

Acortatarins A and B, two novel antioxidative spiroalkaloids with a naturally unusual morpholine motif from Acorus tatarinowii.

Acortatarins A (1) and B (2), two novel spiroalkaloids with a naturally unusual morpholine motif, were isolated from the rhizome of Acorus tatarinowii. Their structures with absolute configuration were determined by spectroscopic methods, X-ray diffraction analysis, and Mosher's method. Importantly, compound 1 could significantly inhibit reactive oxygen species production in high-glucose-stimulated mesangial cells in a dose- and time-dependent manner.